Tank closure assembly

Abstract

A tank closure assembly adapted to releasably couple tank sections formed by transversely splitting an integral bag-molded fiber-reinforced tank. According to one aspect of the invention, the assembly includes external circumferential flanges secured to the tank sections adjacent their severed faces and in opposed relation to each other. An O-ring seal, disposed externally of the tank sections and between the flanges, is compressed into sealing engagement with surrounding surfaces, by tightening of a circumferential band encircling the flanges, to seal the tank sections at their plane of separation. According to another aspect of the invention, the assembly includes a unitary clamping band having hooked ends which engage grooves adjacent the severed faces of the tank sections and the clamping band retains a pair of O-rings which seal the tank at their plane of separation. A method of machining a tank to simultaneously form the split sections and suitable flanges receiving grooves thereon is disclosed, as well as a method of pressure-testing the machined tank sections prior to assembly of the flanges and O-ring seal.

What is claimed is: 
     
       1. A molded, fiber-reinforced, plastic split tank assembly comprising a pair of tank sections having mating faces at a transverse plane, the sidewalls of each tank section having a substantially uniform outside diameter in a zone adjacent its respective face, a nonintegral, circumferential, external flange on each tank section adjacent the face thereof, said flanges each being formed separately from the sidewalls of the tanks, means for axially locking said flanges in position on said tank sections, O-ring means on the exterior of the tank sections and between said flanges, said O-ring means being adapted to sealingly engage external surfaces of said tank section adjacent said faces, circumferential clamping means encircling and drawing said flanges axially together to squeeze said O-ring means and cause it to constrict radially inwardly into said sealing engagement with the exterior surfaces of said tank sections, means defining a circumferential groove on each side of said tank sidewalls adjacent said faces, said grooves having rearwardly facing abutment surfaces, said flanges having portions extending into said grooves including surfaces in engagement with said abutment surfaces, interengagement between said flanges and said grooves providing said axial locking means, said flange being provided in a circular configuration with a single, radial split, said flanges being formed of a material having sufficient resilience to be elastically expanded radially outwardly to permit assembly of said flanges in said grooves, said flanges being formed of steel flat stock rolled into a circular configuration corresponding to the outside diameter of the tank sections, and a reverse fold of material of said steel stock forming said engagement surface. 
     
     
       2. A tank assembly as set forth in claim 1, wherein said flanges include conical skirt portions extending radially outwardly and forwardly from said reverse fold portions, said circumferential clamping means including conical surface portions complementary to the conical configuration of said flanges skirt portions. 
     
     
       3. A tank assembly as set forth in claim 2, wherein said clamping means is a band having at least one radial split, and means to draw the ends of said band at said split together. 
     
     
       4. A method, fiber-reinforced, plastic split tank assembly comprising a pair of tank sections having mating faces at a transverse plane, the sidewalls of each tank section having a substantially uniform outside diameter in a zone adjacent its respective face, a nonintegral, circumferential, external flange on each tank section adjacent the face thereof, said flanges each being formed separately from the sidewalls of the tanks, means for axially locking said flanges in a position on said tank sections, O-ring means on the exterior of the tank sections and between said flanges, said O-ring means being adapted to sealingly engage external surfaces of said tank sections adjacent said faces, circumferential clamping means encircling and drawing the flanges axially together to squeeze said O-ring means and cause it to constrict radially inwardly into sealing engagement with the exterior surfaces of said tank sections, means defining a circumferential groove on each side of said tank sidewalls adjacent said faces, said grooves having rearwardly facing abutment surfaces, said flanges having portions extending into said grooves including surfaces in engagement with said abutment surfaces, interengagement means between said flanges and said grooves providing said axial locking means, said O-ring means comprising a pair of O-rings received within second grooves in said tank sections, said second grooves being positioned between a mating face and the first groove. 
     
     
       5. A molded, fiber-reinforced plastic split tank assembly according to claim 4, wherein said O-rings are covered by an endless circumferential band. 
     
     
       6. A molded fiber-reinforced plastic split tank assembly according to claim 5, wherein said endless band compresses the O-rings twenty percent.